remove genericgeometry subdirectory from dune-geometry

The removal of the genericgeometry subdirectory in dune-geometry will require some minor changes to dune-grid. This merge request collects those and should be merged once the corresponding branch in dune-geometry is merged, too.

dune/grid/uggrid/uggridindexsets.hh

@@ -11,6 +11,7 @@
 #include <set>
 
 #include <dune/common/hybridutilities.hh>
+#include <dune/common/std/type_traits.hh>
 #include <dune/grid/common/grid.hh>
 
 namespace Dune {